Posts Tagged ‘LFTR’

Thorium is a viable alternative to uranium for power generation with some huge potential advantages. It is a shame that the United States is not aggressively pursuing it as an energy source. China has been exploring the use of thorium and just announced a rapid acceleration in their development schedule.

According to the South China Morning Post…

A team of scientists in Shanghai had originally been given 25 years to try to develop the world’s first nuclear plant using the radioactive element thorium as fuel rather than uranium, but they have now been told they have 10.

But the Chinese are working toward the holy grail of thorium reactors: a Liquid Fluoride Thorium Reactor (LFTR or “lifter”). Here is a nice “TED.com” video on the LFTR concept.

China’s appetite for energy is growing by leaps and bounds. Coal is their primary source of electricity, but the resulting smog chokes their cities. Coal will continue to be heavily utilized in China in coming years, but they see thorium a likely route to a cleaner future. They currently have nearly thirty nuclear reactors of various types under construction to meet some of the growing demand. But the LFTR has the greatest potential for fuel supply, non-proliferation, and minimal long term radioactive risk.

It is sad that the great United States may have to learn this lesson from the Chinese.

Check this picture out. It is a crane lifting a 40 meter wide, 4.5 cm thick dome for the top of a nuclear reactor containment building under construction in China. The containment building is extraordinarily massive, the dome alone weighs 655 tonnes (1.4 million pounds).

Believe it on not, the containment building’s purpose is to capture a steam explosion.

Steam Explosion

Water boils at 100°C at one atmosphere of pressure, but the boiling temperature goes up at higher pressures. For example, the water in your car radiator will go to higher than 100°C without boiling because the radiator is pressurized to about 2 atmospheres when the car is warmed up. What happens if the pressure is suddenly released by a puncture or someone foolishly removing the radiator cap? See the video below for a steam explosion…

Carnot engine efficiency increases with increasing temperature, so there is a great advantage to running a nuclear reactor (or any heat engine) at high temperatures, which requires very high pressures to keep the reactor’s water from completely boiling. Conventional boiling water reactors and pressurized water reactors operate at around 70 atmospheres and 160 atmospheres to achieve temperatures of 285°C and 315°C respectively. If water escapes from the reactor for any reason it will instantly expand to about 1600 times its liquid volume as it explodes into steam. The containment building is supposed to capture that exploding steam. It is so massive because it must restrain the steam under great pressure without exploding itself.

Containment building

But this type of massive containment building would not be necessary for a Liquid fluoride Thorium Reactor (LFTR)! This type of reactor concept does not use water to transfer heat away from solid pieces of fissioning metals. Instead, thorium is dissolved in liquid fluoride salts, where it is converted to uranium233, which fissions and generates heat. One of the beauties of the LFTR is that the liquid fluoride salts can go to incredible temperatures before they boil – temperatures vastly exceeding the operating temperature of the reactor. Consequently, the reactor operates at atmospheric pressure – no high pressure needed. In the event of a liquid leak there would be no explosive effect like the water instantly boiling into steam in a conventional reactor.

The LFTR would operate at around 700°C, reaching a much higher carnot efficiency than boiling water reactors or pressurized water reactors. Yet the fluid medium of the LFTR would not boil until reaching the extraordinary temperature of about 1400°C.

Here is a video that has already been seen by over 300,000 times. It is well worth your while if you have not alreardy seen it. It is two hours of shoestring production, but rich in content.

Kirk Sorensen is an aerospace engineer with a passion for promoting Thorium energy. Not just any Thorium energy, but specifically Liquid Floride Thorium Reactors (LFTR – pronounced “lifter”). You can see much more at EnergyFromThorium.com.

Kids in the US spend about 12,000 hours sitting in classrooms by the time they graduate from high school. Vast amounts of that time are wasted on nonsense and trivialities. If 0.2% of that time were spent on getting them to understand the content of this video, it would change the world.